I really, really liked it personally.
But, here's the thing. You had to play it a little, spend like 3 days modding it, play it a little, spend 3 more days modding it, then play it again.
And... spoiler alert... mages are OP and blood mages are OP as hell. That's just a function of the game itself rather than the mods.
But they tried to do some stuff in DA:O that isn't new but really should be part of all fantasy games. With the fade crap it felt like magic was more "magicky" and less "the science of fireballs". Even though it really was the science of fireballs. They put a fair amount of effort into worldbuilding. The factions are trope-ish but distinct. You understand why the Chantry exists to regulate the Mages, and there's an actual irresolvable conflict at the heart of the two organizations. Which, of course, bioware proceeds to completely shit on with sequels. Best part of the game and bioware misses their very own fucking point. But whatever, that doesn't make DA:O any better or worse.
Successor to BG2... I dunno. But it was one of the better fantasy games to come out since BG2 I guess. Not the hands down absolute best, but one of the better.